Verti-what?!?

With a blog called Blooms and beats and the bits in between, one would have imagined that I'd spend a bit of time talking about Blooms and Beats. To date, all that's been served up is kind of like the peanut-butter and jam without the bread.


But, I spent today as a researcher. Searching for information on Verticillium (this is the Wikipedia link) or more specifically V. albo-atrum (this is the Britannica link). Now if any one out there likes gardening, put down your cup of tea and start making notes.

Verticillium, I was reminded, affects too many plants and trees to even start mentioning and we have a few beds in one of the greenhouses that have been affected. We'd love to treat the plants to make them better - but all the reports I found were very gloomy. In fact the one remedy went so far as tto say: "Remove the plant, roots and all and destroy it. If you're going to replant in the same space, wait three years and choose a plant that's resistant to Verticillium."

Three years - that can't be? I read it again to be certain and sure enough - that's what they said, "Three years" - they must be nuts!

Terribly disheartened by that news, I started ferreting through numerous books, databases and the web to find some short course remedies. I spent ages critically evaluating all the data on hand, some of it conflicting of course, seeking a solution that would allow us to replant when the beds fall due in about three weeks.

But before running away with myself a bit here, let me backtrack for those of you who actually are ready to take the aforementioned notes: Verticillium albo-atrum as the Wikipdeia link says in slightly fancier English than I'd care to use is a soil borne fungus. To date there are no certified remedies available and as mentioned before affects numerous trees and succulents. They forgot to mention tomatoes on that list.

A vicious little critter, V. albo-atrumit works it's way up the plants vascular system, often killing one side of the plant from the roots up. In succulents the leaves will often turn yellow and die back, hanging pathetically on the stem. And to make matters worse, it tends to strike in the latter stages of plant growth. Cool and damp conditions are the time to keep an eye out for it. The result is ultimately, how do I put this gently.... death.

Looking forward again, my intense research began to pay off as I started putting a remedy puzzle together.

I found an interesting research paper from the University of Florida, dating back to 1985. There appears to be some remedy in changing the pH of the soil. Dropping the pH of inoculated soil from 7.5 pH to 5.5 pH, reduced the incidence of the disease from 90% infestation to a meagre 17%. That kind of result makes one pay attention! If I ever have it at home, I'll have to consult my best gardening books / the greenie okes at the garden centre to see if there practical way to do it there.

Another suggestion came from a textbook by Ball Publishing, which suggested a fungicide drench. So we're also going to try and use Rovral Flo (iprodione) which is normally used as a foliar spray for Botrytis cineria (most commonly seen as pink spots on your rose blooms) as a drench in order to suppress the symptoms in plants we're not likely to remove. There seems to be no conclusive evidence that it'll work, but we figure it's worth a shot - rather than throwing away thousands of plants.

We're also going to get our hands on a chemical fumigant called Metam-sodium (Herbifume - from Plaaskem is one of the brand names). This 'safe' and easy to handle fumigant apparently kept the disease incidence as low as 7%.

The commercial growers the best remedies are Steam Sterilisation for which you need a boiler and a licence, or fumigation. For domestic growers (i.e: gardeners) few remedies exist - but there is some hope at hand.

Some practical tips are:

• Loosing the plant is almost always inevitable, so the sooner it's removed and destroyed the better . DO NOT COMPOST the affected and try your best to remove all the roots. In fact burning is strongly suggested.
• If the plant is in a pot, get rid of that soil, wash the pot thoroughly with bleach solution and rinse it well.
• Cut ALL nitrogen rich fertilizers into the affected areas, but bolster the use of PHOSPHORUS based fertilizer in the immediate area.
• If you're dealing with a garden bed try to find an economical way to drop the pH of the soil.
• Herbifume may well be out of reach to the domestic user now that I think of it, but you'll never know if you don't ask... Obviously any fumigant will kill any plants in the ground.
• Finally, select Verticillium resistant plants when you do replant. Your garden centre specialists should know which plants are safe.

So tomorrow is action day one. We get out drenching machine and a few watering cans and start drenching like crazy. After the harvest we'll fumigate the affected beds and after the next harvest we'll steam sterilize the entire greenhouse (an annual event). Here goes to getting rid of the Verticillium!!!!